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Perfluorooctane sulfonate in fish and water

Perfluorooctane sulfonate (PFOS) is exceptionally persistent, ubiquitous in the environment and subject to long-range transport. It is of ecological concern, given its widespread occurrence and its bioaccumulation, persistence, developmental toxicity, immunotoxicity and hepatotoxicity in animals. The Perfluorooctane Sulfonate (PFOS) in Fish and Water indicators report whether PFOS concentrations in fish tissue and water exceed the Federal Environmental Quality Guidelines (the Guidelines).

Perfluorooctane sulfonate in fish tissue

Between 2011 and 2014, Environment and Climate Change Canada collected fish from 11 drainage regions and analyzed PFOS concentrations in their tissue. The analysis found that the concentration of PFOS was below the Guidelines for fish health in all fish from all sampled drainage regions.

In some instances, PFOS concentrations in fish exceeded the Guidelines for the protection of mammals and birds that eat the fish, suggesting that this compound could threaten predators higher in the food chain. Seven (7) out of the 11 sampled drainage regions had concentrations of PFOS that exceeded the wildlife diet guidelines. These results are similar to those collected during a previous sampling campaign conducted over the 2006 to 2010 period.

Note: Measurements were made on a sample of 523 fishes of representative species (lake trout, walleye, brook trout and chain pickerel) collected from 11 drainage regions from 2011 to 2014.Source: Environment and Climate Change Canada (2016) Freshwater Quality Monitoring and Surveillance Division.

Perfluorooctane sulfonate trend in fish in Lake Ontario

To provide context on changes through time, additional data showing PFOS concentrations in Lake Ontario fish are presented for the period 1979 to 2014. PFOS concentrations in Lake Ontario lake trout showed an overall increase between 1979 and 2000. However, after 2000, the concentration stabilized for a few yearsFootnote [1] and then began to decrease. These results suggest that, although PFOS in Lake Ontario lake trout may have stopped increasing in response to the voluntary and regulatory actions, corresponding concentration declines in fish have just begun to be observed. Levels of PFOS in Lake Ontario lake trout were well below the Guideline for fish tissue in all collection years. This suggests a low probability of adverse effects to fish related to PFOS exposure. In contrast, PFOS levels were all above the Guidelines for wildlife diet and could represent a risk to wildlife that feed on fish.

The chart shows the annual geometric average concentration, expressed in nanograms per gram wet weight, of perfluorooctane sulfonate in lake trout from Lake Ontario from 1979 to 2014. The concentration can be compared with the Federal Environmental Quality Guidelines for perfluorooctane sulfonate in fish tissue (8300 nanograms per gram wet weight) and wildlife diet (4.6 nanograms per gram wet weight for mammals and 8.2 nanograms per gram wet weight for birds). Data is provided from four different datasets. Perfluorooctane sulfonate concentrations in Lake Ontario lake trout showed an overall increase between 1979 and 2000 followed by a decrease. For all collection years, levels of perfluorooctane sulfonate in Lake Ontario lake trout were well below the Guideline for fish tissue but above the Guidelines for wildlife diet.

Note: The concentration of perfluorooctane sulfonate in fish is expressed as an annual average (geometric mean). Four datasets are represented in this chart. The first dataset comes from a study done by Furdui from the Ontario's Ministry of the Environment in collaboration with Fisheries and Oceans Canada and Environment and Climate Change Canada. The three other datasets come from Environment and Climate Change Canada's Freshwater Quality Monitoring and Surveillance program. The second dataset, Environment and Climate Change Canada - Retrospective analysis, comes from a retrospective analysis conducted using specimens from the National Aquatic Biological Specimen Bank. The third dataset, Environment and Climate Change Canada - AXYS Analytical study, is analyses conducted by AXYS Analytical Services Ltd. and the fourth, Environment and Climate Change Canada - National Laboratory for Environmental Testing, is from analyses conducted by the National Laboratory for Environmental Testing. The top dotted line represents the Federal Environmental Quality Guideline for fish tissue. The lower two dotted lines represent the Federal Environmental Quality Guidelines for wildlife diet (mammals and birds).Source: Environment and Climate Change Canada (2016) Freshwater Quality Monitoring and Surveillance Division.

Perfluorooctane sulfonate in water

Between 2011 and March 2016, Environment and Climate Change Canada collected water from eight drainage regions and analyzed the samples for PFOS concentrations. The analysis found that all water samples had PFOS concentrations at least 50-fold lower than the Guideline for water.

Comparison between perfluorooctane sulfonate concentrations in water and the Federal Environmental Quality Guideline, 2011 to 2016

Sampled drainage region

Sample size(number of water samples)

Did any water sample collected in the drainage region return a concentration reading above the guideline for perfluorooctane sulfonate in water?